I ended up going with a ebay used dell/hp sff i7 4770 with pcie. It will replace a n54l which is struggling already with pfblockerng (large list), snort (alerts only) etc using 8gb ram out of 16.
I already have dual and quad intel nics ready to go in.
vpn to connect to firewall.
multiple vpn points of presence to accommodate gamers and streamers.
snort and one day suricata.
1/3 the price of a appliance for me and way more powerful, cheap easy to replace.